I must admit I rarely had any trouble with hifi dealers - much less so than shopping in general.
Hi-fi experience in Tottenham Court Road, there was a dealer who looked like bit like Charles Dance and happily demo'd me stuff when I clearly was a teenager who couldn't afford it.
Sevenoaks hifi in Woolwich, every sales guy in there was always helpful even though I spent a grand sum of **** all. No come to think of it, I bought a C60 version of the TDK S-AX chrome cassette.
I feel kind of bad they're both closed down years ago.